1. Technical Field
The present invention relates to an apparatus and method for quenching thin walled metal hollow casings and in particular to an apparatus and method for quenching thin walled metal hollow casings manufactured by blow molding.
2. Description of the Background Art
The inventor of the present invention has applied for a patent entitled “A method for manufacturing thin walled metal hollow casing by blow moulding” in a number of territories including U.S.A. with U.S. patent application Ser. No. 09/424,235 (now U.S. Pat. No. 6,261,392 issued Jul. 17, 2001) and Europe with European Patent Application No. 98919699.3 and the present application discloses an improvement to inventions in this general area. After considerable testing of the method disclosed in the above referenced application in combination with a review of blow molding processes described in the prior art, an improved apparatus and method have been invented which overcome a number of inherent problems with previous methods of quenching blow molded thin walled metal hollow casings.
The cooling processes used in methods disclosed in the prior art do not provide even cooling to the preheated casing. Cooling occurs more rapidly on regions of the external surface of the casing which are proximal to cooling channels provided on a number of the molding tools of the prior art thereby effecting the quality of the blow molded casing. The speed of the cooling process also needs to be optimized in order to improve the efficiency of the manufacturing method.